1. 在舞台后；在舞台旁
When an actor or entertainer goes offstage, they go into the area behind or to the side of the stage, so that the audience no longer sees them.
2. （戏剧中声效）来自后台的，出自舞台表演区外的
In a theatre, offstage sounds are produced behind or to the side of the stage, so that the audience hears them but does not see them produced.
3. （演员、表演者）台下的，现实生活中的
Offstage is used to describe the behaviour of actors or entertainers in real life, when they are not performing.